README File for Census 2000 Summary File 1 Delivered via FTP

Note: We are unable to provide one-on-one support for applications of these data to specific spreadsheet or data base software. However, detailed instructions for loading an ASCII file into Access 97 can be found at http://www.census.gov/support/SF1ASCII.html . On some systems, there may be a password request. Select cancel and you will go directly into the instructions.

About the FTP Application
About the FTP Application

This FTP (File Transfer Protocol) application is intended for experienced users of census data, compressed files, and spreadsheet/database software. It provides quick access to data users, such as State Data Centers and news media, who need to begin their analysis immediately upon data release. Due to the size of the files, the FTP user should have a fast file transfer capability.

Each state directory provides all files available for the identified state. Once uncompressed, the data are in a flat ASCII format. The geographic file is in a fixed-field format; the two data files are in comma delimited format. No software is provided. Users of the FTP application need to unzip the compressed file after downloading, then import it into the spreadsheet/database software of their choice for data analysis and table presentation.

Other Sources of the Data Other Sources of the Data

The Census Bureau releases most Census 2000 data on a state-by-state basis. Tables generally are available in American FactFinder (factfinder.census.gov) the day of the release of the designated state file. Within American FactFinder, individual tables can be downloaded in a text delimited or comma delimited format.

For users without immediate need for the data, CD-ROMs containing the data and access software are scheduled for shipping shortly after the state file release. They can be ordered from the Census Bureau's Customer Services Center at 301-457-4100.

FTP File Transfer

The FTP directory for Summary File 1 (SF1) is at http://www2.census.gov/census_2000/datasets/ When the SF1 data are added to the respective state directories, there will be 40 files for each state-- a geographic header file and thirty-nine data files. See the chart below for more information on the data segments.

To facilitate transferring multiple files, we suggest using features commonly found in most vendor's FTP utility. In the UNIX environment, the "mget" subcommand allows transferring multiple files using a wildcard character. For example, once you have navigated into the SF1 directory for Nebraska, you can download all 40 SF1 files with the following two ftp subcommands:

ftp>prompt off	(to avoid being asked for verification of each file, optional)

ftp>mget ne*

When testing the download in a PC environment, we used the ws_ftp product. This product, and many other FTP products developed for the PC environment, allows individual multiple file selection using the control key or block multiple file selection using the shift key.

File Naming Conventions

File naming conventions have changed since the release of the Redistricting data. The new convention is ss000yy_uf1.zip where ss is the USPS state abbreviation and yy is the number (01-39) of the file segment. The geoheader file name is ssgeo_uf1.zip .

File Information

Once uncompressed, these files are in flat ASCII format. The geographic header file (see below) contains fixed fields while the data files (File01 through File39, see below), including the geographic link fields, are in comma-delimited format. These files have been constructed in a UNIX environment. They use an ASCII linefeed, chr(10), to indicate a new record.

For successful use with many programs running in a Windows environment, these files need to be modified to use the ASCII carriage return/linefeed sequence, chr(13) + chr(10) as a record terminator. This is an easy step in the UnZIP process using any UnZIP software which offers the conversion option. We tested PKZIP for Windows, version 4.00 following the steps outlined below. This PKZIP shareware can be downloaded from www.pkware.com. After installing PKZIP, do the following:

--Select the file

--Select the Extract option on the tool bar

--Select the options button at the bottom of the Extract page

--Under the Miscellaneous section, select the "DOS - convert to CR/LF"

The resulting file will meet the ANSI MS-DOS/Windows standard used by Access 97 and other MS Windows-based programs. If the data are being processed in a UNIX environment, they can be unzipped using any standard ZIP/UnZIP package.

These FTP data are available as compressed files at the 90% (approximately) file compression ratio. If you are using a modem/telephone line link to the Internet, we do not recommend using the FTP option.

Segmented Data Segmented Data

The data in the redistricting files and other Census 2000 summary files are segmented. This is done so that individual files will not have more than 255 fields, facilitating exporting into spreadsheet or database software. In short, to get the complete data set for SF1 files, users must FTP all forty files in the state directory.

These test files contain:

File Name

Number of

Data Items

Starting

Matrix

Number

Ending

Matrix

Number

Geographic Header File

011

222